1. Field of the Invention
The present invention relates to controller-assisted shifting of manually shifted transmissions. In particular, the present invention relates to a control system/method for a manually shifted transmission that, in a preferred embodiment, will (i) sense an operator intent to shift and automatically minimize driveline torque, minimizing torque lock and allowing an easy shift to neutral; and (ii) upon sensing a shift to main section neutral, then sense a target gear ratio, cause the engine to rotate at a substantially synchronous speed for engaging the target ratio, and inhibit/prohibit shifting from neutral until substantially synchronous conditions for engaging the target gear ratio are sensed.
In particular, the present invention relates to a detent plunger assembly for a controller-assisted, manually shifted transmission system of the type described.
2. Description of the Prior Art
Controller-assisted, manually shifted transmission systems are known in the prior art. Typically, such systems include sensors, actuators and a microprocessor-based controller and will automatically assist manual shifting by sensing an operator intent to shift and cause a reduction in driveline torque and/or by sensing an intended target ratio and causing synchronous conditions for engaging the target ratio. Such controller-assisted systems may be seen by reference to U.S. Pat. Nos. 4,593,580; 4,850,236; 4,676,115; 5,582,558; 5,755,639; 5,735,771; 6,015,366 and published British patent application GB 2,335,010A, the disclosures of which are incorporated herein by reference.
Transmission systems having controls and/or sensors in the shift knobs are known in the prior art, as may be seen by reference to U.S. Pat. Nos. 4,723,642; 5,228,361 and 5,957,001, the disclosures of which are incorporated herein by reference.
The prior art systems were not totally satisfactory, as they required the added cost of providing individual or power synchronizers, they required considerable additional sensors and/or actuators, they required the driver to provide a separate signal of a target ratio, they did not provide a high resistance to shift lever jumpout while still providing high shift quality, and/or did not, with a high degree of reliability, prevent or inhibit non-synchronous shifting.